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1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2012 Regents of the University of California
4  */
5 
6 #ifndef _ASM_RISCV_PROCESSOR_H
7 #define _ASM_RISCV_PROCESSOR_H
8 
9 #include <linux/const.h>
10 #include <linux/cache.h>
11 
12 #include <vdso/processor.h>
13 
14 #include <asm/ptrace.h>
15 
16 #ifdef CONFIG_64BIT
17 #define DEFAULT_MAP_WINDOW	(UL(1) << (MMAP_VA_BITS - 1))
18 #define STACK_TOP_MAX		TASK_SIZE
19 
20 #define arch_get_mmap_end(addr, len, flags)			\
21 ({								\
22 	unsigned long mmap_end;					\
23 	typeof(addr) _addr = (addr);				\
24 	if ((_addr) == 0 || (IS_ENABLED(CONFIG_COMPAT) && is_compat_task())) \
25 		mmap_end = STACK_TOP_MAX;			\
26 	else if ((_addr) >= VA_USER_SV57)			\
27 		mmap_end = STACK_TOP_MAX;			\
28 	else if ((((_addr) >= VA_USER_SV48)) && (VA_BITS >= VA_BITS_SV48)) \
29 		mmap_end = VA_USER_SV48;			\
30 	else							\
31 		mmap_end = VA_USER_SV39;			\
32 	mmap_end;						\
33 })
34 
35 #define arch_get_mmap_base(addr, base)				\
36 ({								\
37 	unsigned long mmap_base;				\
38 	typeof(addr) _addr = (addr);				\
39 	typeof(base) _base = (base);				\
40 	unsigned long rnd_gap = DEFAULT_MAP_WINDOW - (_base);	\
41 	if ((_addr) == 0 || (IS_ENABLED(CONFIG_COMPAT) && is_compat_task())) \
42 		mmap_base = (_base);				\
43 	else if (((_addr) >= VA_USER_SV57) && (VA_BITS >= VA_BITS_SV57)) \
44 		mmap_base = VA_USER_SV57 - rnd_gap;		\
45 	else if ((((_addr) >= VA_USER_SV48)) && (VA_BITS >= VA_BITS_SV48)) \
46 		mmap_base = VA_USER_SV48 - rnd_gap;		\
47 	else							\
48 		mmap_base = VA_USER_SV39 - rnd_gap;		\
49 	mmap_base;						\
50 })
51 
52 #else
53 #define DEFAULT_MAP_WINDOW	TASK_SIZE
54 #define STACK_TOP_MAX		TASK_SIZE
55 #endif
56 #define STACK_ALIGN		16
57 
58 #define STACK_TOP		DEFAULT_MAP_WINDOW
59 
60 /*
61  * This decides where the kernel will search for a free chunk of vm
62  * space during mmap's.
63  */
64 #ifdef CONFIG_64BIT
65 #define TASK_UNMAPPED_BASE	PAGE_ALIGN((UL(1) << MMAP_MIN_VA_BITS) / 3)
66 #else
67 #define TASK_UNMAPPED_BASE	PAGE_ALIGN(TASK_SIZE / 3)
68 #endif
69 
70 #ifndef __ASSEMBLY__
71 
72 struct task_struct;
73 struct pt_regs;
74 
75 /*
76  * We use a flag to track in-kernel Vector context. Currently the flag has the
77  * following meaning:
78  *
79  *  - bit 0: indicates whether the in-kernel Vector context is active. The
80  *    activation of this state disables the preemption. On a non-RT kernel, it
81  *    also disable bh.
82  *  - bits 8: is used for tracking preemptible kernel-mode Vector, when
83  *    RISCV_ISA_V_PREEMPTIVE is enabled. Calling kernel_vector_begin() does not
84  *    disable the preemption if the thread's kernel_vstate.datap is allocated.
85  *    Instead, the kernel set this bit field. Then the trap entry/exit code
86  *    knows if we are entering/exiting the context that owns preempt_v.
87  *     - 0: the task is not using preempt_v
88  *     - 1: the task is actively using preempt_v. But whether does the task own
89  *          the preempt_v context is decided by bits in RISCV_V_CTX_DEPTH_MASK.
90  *  - bit 16-23 are RISCV_V_CTX_DEPTH_MASK, used by context tracking routine
91  *     when preempt_v starts:
92  *     - 0: the task is actively using, and own preempt_v context.
93  *     - non-zero: the task was using preempt_v, but then took a trap within.
94  *       Thus, the task does not own preempt_v. Any use of Vector will have to
95  *       save preempt_v, if dirty, and fallback to non-preemptible kernel-mode
96  *       Vector.
97  *  - bit 30: The in-kernel preempt_v context is saved, and requries to be
98  *    restored when returning to the context that owns the preempt_v.
99  *  - bit 31: The in-kernel preempt_v context is dirty, as signaled by the
100  *    trap entry code. Any context switches out-of current task need to save
101  *    it to the task's in-kernel V context. Also, any traps nesting on-top-of
102  *    preempt_v requesting to use V needs a save.
103  */
104 #define RISCV_V_CTX_DEPTH_MASK		0x00ff0000
105 
106 #define RISCV_V_CTX_UNIT_DEPTH		0x00010000
107 #define RISCV_KERNEL_MODE_V		0x00000001
108 #define RISCV_PREEMPT_V			0x00000100
109 #define RISCV_PREEMPT_V_DIRTY		0x80000000
110 #define RISCV_PREEMPT_V_NEED_RESTORE	0x40000000
111 
112 /* CPU-specific state of a task */
113 struct thread_struct {
114 	/* Callee-saved registers */
115 	unsigned long ra;
116 	unsigned long sp;	/* Kernel mode stack */
117 	unsigned long s[12];	/* s[0]: frame pointer */
118 	struct __riscv_d_ext_state fstate;
119 	unsigned long bad_cause;
120 	u32 riscv_v_flags;
121 	u32 vstate_ctrl;
122 	struct __riscv_v_ext_state vstate;
123 	struct __riscv_v_ext_state kernel_vstate;
124 };
125 
126 /* Whitelist the fstate from the task_struct for hardened usercopy */
arch_thread_struct_whitelist(unsigned long * offset,unsigned long * size)127 static inline void arch_thread_struct_whitelist(unsigned long *offset,
128 						unsigned long *size)
129 {
130 	*offset = offsetof(struct thread_struct, fstate);
131 	*size = sizeof_field(struct thread_struct, fstate);
132 }
133 
134 #define INIT_THREAD {					\
135 	.sp = sizeof(init_stack) + (long)&init_stack,	\
136 }
137 
138 #define task_pt_regs(tsk)						\
139 	((struct pt_regs *)(task_stack_page(tsk) + THREAD_SIZE		\
140 			    - ALIGN(sizeof(struct pt_regs), STACK_ALIGN)))
141 
142 #define KSTK_EIP(tsk)		(task_pt_regs(tsk)->epc)
143 #define KSTK_ESP(tsk)		(task_pt_regs(tsk)->sp)
144 
145 
146 /* Do necessary setup to start up a newly executed thread. */
147 extern void start_thread(struct pt_regs *regs,
148 			unsigned long pc, unsigned long sp);
149 
150 extern unsigned long __get_wchan(struct task_struct *p);
151 
152 
wait_for_interrupt(void)153 static inline void wait_for_interrupt(void)
154 {
155 	__asm__ __volatile__ ("wfi");
156 }
157 
158 struct device_node;
159 int riscv_of_processor_hartid(struct device_node *node, unsigned long *hartid);
160 int riscv_early_of_processor_hartid(struct device_node *node, unsigned long *hartid);
161 int riscv_of_parent_hartid(struct device_node *node, unsigned long *hartid);
162 
163 extern void riscv_fill_hwcap(void);
164 extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
165 
166 extern unsigned long signal_minsigstksz __ro_after_init;
167 
168 #ifdef CONFIG_RISCV_ISA_V
169 /* Userspace interface for PR_RISCV_V_{SET,GET}_VS prctl()s: */
170 #define RISCV_V_SET_CONTROL(arg)	riscv_v_vstate_ctrl_set_current(arg)
171 #define RISCV_V_GET_CONTROL()		riscv_v_vstate_ctrl_get_current()
172 extern long riscv_v_vstate_ctrl_set_current(unsigned long arg);
173 extern long riscv_v_vstate_ctrl_get_current(void);
174 #endif /* CONFIG_RISCV_ISA_V */
175 
176 #endif /* __ASSEMBLY__ */
177 
178 #endif /* _ASM_RISCV_PROCESSOR_H */
179